Can anyone compare these to the Sennheiser HD 598s, which today only are going for $100 on Amazon? I'm pretty new to high-end headphone shopping. Are these AKGs worth paying the extra $100, or should I cancel my order?

If you want some great high quality cables of different lengths made for the 598s, go to eBay electronics and search Sennheiser HD 598 cable. Very high quality and not expensive. Not sure about sound improvement.